Method of disassembling sheet metal assemblies

ABSTRACT

A method and apparatus for disassembling or removing an elongated, flexible metal strip joined, such as by spot welding, to a relatively rigid base member. The method includes loosening a first end of the strip from the base member. A tool is provided having a bifurcated end portion adapted to be rotated about an axis generally aligned with the mid-plane of the bifurcation. The first end portion of the strip is positioned in the bifurcation. Thereafter, the tool is rotated about its axis causing the strip to be wound on the tool and ripped from the base member. The tool disclosed is especially suited for carrying out the method and includes a generally conical, truncated body with a bifurcated cylindrical portion extending outwardly from the small diameter end of the body. When used to carry out the method, the relationship of the bifurcated portion conical body causes the strip to wind up on the conical body which makes the strip much easier to remove from the tool.

United States Patent [151 3,688,383

Martin Sept. 5, 1972 [54] METHOD OF DISASSEMBLING SHEET METAL ASSEMBLIES Primary Examiner-Charlie T. Moon [72] Inventor: Albert Michael Martin, Cleveland, Atmmey Fay Sharpe and Mulhonand R A Bod I 57 ABSTRACT d to [73] sslgnee f M u y A method and apparatus for disassembling or remov- [22] Filed: Apl'll 23, 19 0 ing an elongated, flexible metal strip joined, such as by A L N 31,085 spot welding, to a relatively rigid base member. The PP 0 method includes loosening a first end of the strip from the base member. A tool is provided having a bifur- U-S- D, cated end portion adapted to be rotated about an axis 225/93 generally aligned with the mid-plane of the bifurca- [51] Int. Cl. ..B23p 19/02 i The first end portion f the Strip is positioned in [58] Fleld of Search ..29/403, 427, 200 D; 220/52; the bifurcation. Thereafter, the tool is rotated about 225/1 93; 30/165; 156/344 its axis causing the strip to be wound on the tool and ripped from the base member. The tool disclosed is [56] References C'ted especially suited for carrying out the method and in- UNITED STATES PATENTS cludes a generally conical, truncated body with a bifurcated cylindrical portion extending outwardly et a1 from the mall diameter end of the when used 2,149,869 3/1939 Ri ngel ..225/ l to can-y out the method, the relationship of the bifur 2,71 1,109 6/ 1955 Glllstrom ..30/ 165 UX cated portion conical body causes the strip tO wind up 2,719,358 10/1955 Lassen ..3()/ 165 on the conical body which makes the Strip much easi 2,777,479 1/ 1957 Beanum ..225/l X er to remove from the tool 2,919,049 12/1959 Berry ..220/52 3,014,271 12/ 1961 Englund ..29/427 UX 5 Claims, 4 Drawing Figures PATENTEDSEP 5 I912 3 688 383 L3. as 24 4 Fig 3 P77 4 INVENTOR. ALBERT M. MARTIN BY F5 w xwwflw ATTORNEYS.

METHOD OF DISASSEMBLING SHEET METAL ASSEMBLIES The subject invention relates and is directed to a method and apparatus particularly suited for disassembling sheet metal assemblies.

The invention is especially suited for use in removing welded, sheet metal portions of automobile bodies and will be described with particular reference thereto; however, it will be appreciated the invention is capable of broader application and could be used for disassembling many types of sheet metal assemblies connected other than by welding.

Automobile body assemblies, such as doors, quarter panels, and the like, are generally made from stamped sheet metal members having flanged edge portions. The flanges are normally joined to other body assemblies or the frame by spot welds spaced at frequent intervals of, for example, such as three-fourths to 1% inches apart.

In repairing damaged body assemblies or portions thereof, it has generally been the practice to use cutters which cut through the sheet metal and rip it by means of an air-actuated hammer to affect removal of the damaged section. The cutters leave a narrow edge member together with the formed flange that is welded to the frame or other base assembly. Removal of the edge members and the flanges has been a constant source of trouble.

Two methods have previously been used for removing the edge members and flanges. One method has been simply to break the spot welds by using a hammer and cold chisel. This method is generally extremely difficult and requires a substantial amount of time. The other method has been to use a cutting torch to cut the flange from the base assembly. Because the typical auto body has a substantial of insulation, wiring, and the like, the cutting torch technique has resulted in flash fires. Frequently, both wiring and insulation has been damaged. Additionally, as can readily be appreciated, the fires are a great source of annoyance and hazard to the body shop personnel.

The subject invention provides a method and an apparatus which overcomes the above-problems and allows disassembly of sheet metal assemblies rapidly and with a minimum of effort.

Generally speaking, the method of this invention comprises a unique series of steps for removing the elongated strip of flexible metal which comprises the flange and is joined along its length to the relatively rigid base member. Normally, the method comprises the steps of:

a. separating an end portion of the strip from the base member;

b. providing a tool having a bifurcated end portion adapted to be rotated about an axis generally aligned with the mid-plane of the bifurcation;

c. positioning the end portion of the strip in the bifurcation in a direction inclined slightly relative to the axis; and

d. thereafter, the tool or the bifurcated member is rotated about its axis causing the strip of metal to be wound up on the member and ripped from the base member.

Generally, the rotation of the bifurcated member is accomplished by a standard air-actuated ratchet wrench rotated intermittently or at varying revolutions per second. It has been found that the intermittent operation of the rotating device, whether it be an air hammer, air-actuated ratchet wrench or the like, facilitates the tearing of the elongated strip from the base member.

Generally, and in accordance with a second aspect of the invention, the tool member includes a conically shaped body portion having a central axis and connecting means at the large diameter end of the body for attaching it to an air-operated wrench or the like. At the smaller diameter end of the conical portion, a cylindrical shaft section extends outwardly a substantial distance. The cylindrical end portion is provided with a bifurcation which extends from its outer free end to closely adjacent the conical portion.

To use the tool, the end portion of the metal strip is positioned in the bifurcation at a point closely adjacent the conical body portion. Rotation of the member causes the strip to be ripped from the base member and wrapped spirally upon the conically shaped portion. After the completion of the strip removal operation, the strip can be easily removed from the member because of the fact that it is wound upon the conical surface in single layer convolutions and the natural spring-back of the metal strip causes it to separate a slight distance from the member. The wound strip can be simply slid off the cylindrical end section of the member.

Accordingly, a primary object of the invention is the provision of an improved method and apparatus for removing elongated strips of flexible metal from a relatively rigid base member.

Yet another object of the invention is the provision of a tool particularly suited for performing the described disassembly method which tool permits the wound strip to be rapidly removed therefrom.

Still a further object of the invention is the provision of a method particularly suited for removing welded flange portions of auto body assembly from the auto frame and other body assemblies during body repair work.

A further object is the provision of a tool of the type described which is adapted to be readily connected with a standard air-actuated ratchet wrench or the like, and used for ripping sheet metal strips from base assemblies.

Still a further object of the invention is the provision of a method of the general type described which greatly facilitates disassembly of sheet metal assemblies.

These and other objects will become apparent from the following description when read in conjunction with the accompanying drawings wherein:

FIG. 1 is a pictorial view showing the invention being used to separate a welded flange of sheet metal from an auto body frame member;

FIG. 2 is a detailed view of the preferred form of tool used in practicing the method;

FIG. 3 is a view taken on line 3-3 of FIG. 2 and showing the means for connecting the tool to an air-actuated ratchet wrench or the like; and,

FIG. 4 is a view taken on line 4-4 of FIG. 2 showing the bifurcated end portion of the tool.

Referring now to the drawings wherein the showings are for the purpose of illustrating a preferred embodiment of the invention only, and not for the purpose of limiting same, FIG. 1 shows in pictorial view a portion of an auto body and frame including a relatively rigid steel channel member to which is joined an elongated flange strip 12. In the embodiment under consideration, the strip 12 is joined by a closely spaced series of spot welds 14 as is customary in auto body assemblies. As previously discussed, it is been the practice to remove such flange strips from the base member through the use of a hammer and cold chisel or a cutting torch. In accordance with the preferred form of the present invention, the strip is removed by loosening one end portion of the strip and inserting it in a bifurcated member adapted to be rotated about an axis extending through and generally parallel with the longitudinal extent of the bifurcation. The bifurcated member is preferably rotated through the use of a conventional air wrench, although other types of power operated rotating means could be used.

With the strip positioned in the bifurcation operation of the air wrench causes the strip 12 to be ripped from the base member 10 and wound up on the bifurcated member. It has been found that the removal operation is facilitated if the wrench is operated intermittently and at a relatively low number of revolutions per second, e.g., l to 4 rps. The intermittent low speed operation provides a rotary impact which tends to rip the spot welds loose somewhat easier.

The preferred apparatus or tool used for carrying out the method is as shown in FIGS. 2 through 4. FIG. 2 shows the tool 16 as being provided with a connecting portion 18 which is preferably a 9% inch socket arranged so that the tool can be rapidly connected to a conventional air-operated ratchet wrench such as wrench 18 of FIG. 1. Immediately adjacent the connecting portion 12 and axially aligned therewith is a conically shaped body section 20. Section 20 tapers relatively uniformly from its large diameter end 22 to its smaller diameter end 24. Extending axially outward from end 24 is a uniform diameter cylindrical portion 26. The cylindrical portion 26 is provided with a slot 28 which extends inwardly from the free end 30 to a point closely adjacent the juncture between cylindrical portion 26 and the small diameter end 24 of the conical portion 20. Preferably, the slot is formed diametrically through the cylindrical portion 26 and extends into the conical body portion a short distance. It is to be understood, however, that the orientation of the slot could vary somewhat from that shown.

With the tool 16 connected to the air-operated ratchet wrench 18, the end portion of strip 12 is positioned in the slot 28 and slid to a position closely adjacent the juncture between cylindrical portion 26 and conical portion 20. Preferably, the end of the strip is angled slightly relative to the slot so that when the airoperated ratchet wrench 18 is operated at relatively low speed, the end of the strip will begin wrapping spirally up the conical surface of portion 20. By varying the speed of the wrench 18, the strip can be rapidly wound up on the conical portion and torn from the base frame member 10.

As can be appreciated, after the strip is wound on the conical surface 20, removal from the tool is relatively simple. Since the strip is not wound in stacked convolutions, the natural spring-back of the metal strip allows it to sefilarate a short distance from the conigal ortion 20. us, merely by tapping the end of t e ool 16 against a hard surface, the wound strip can be removed of the cylindrical end of the tool.

If the strip should he accidentally torn before it is completely removed from the base member, the wound portion is simply stripped off the tool 16 and a new end formed on the remaining portion of the strip which is still attached to the base member. The bifurcated member is again connected to the end portion and the operation repeated.

As can be appreciated, the method and apparatus of the invention greatly facilitates the removal and/or disassembly of sheet metal assemblies of the type described. Obviously, modifications and alterations of the preferred embodiments will occur to others upon a reading and understanding of the specification. It is my intention to include all such alterations and modifications as part of my invention insofar as they come within the scope of the appended claims.

Having thus described my invention, I claim:

1. A method of disassembling assemblies of the type comprising a sheet metal panel having at least one edge bent over to provide a relatively narrow elongated flange which is joined to a relatively rigid metal base member by spot welds positioned along the length of said flange at relatively close intervals, said method comprising the steps of:

a. cutting said panel along said edge flange relatively closely adjacent said base member to remove the body portion of said panel while leaving said flange joined to said base member;

b. separating an end portion of said flange from said base member and bending the free end portion away from said base member;

c. providing a tool having a bifurcated end portion adapted to be rotated about an axis generally aligned with the longitudinal extent of the bifurcation;

d. positioning the free end portion of the strip in the bifurcation; and,

e. rotating the tool about said axis to cause said flange to be wound up said tool and said spot welds sequentially broken to thereby remove said flange.

2. The method as defined in claim 1 wherein said tool is rotated at intermittently varying revolutions per second.

3. The method as defined in claim 1 wherein said tool is rotated at below 10 revolutions per second.

4. The method as defined in claim 1 wherein said tool is rotated intermittently.

5. The method as defined in claim 1 wherein said flange is wound upon said tool in a direction such as that the portion of the flange which has not been removed is always between the tool and the base member. 

1. A method of disassembling assemblies of the type comprising a sheet metal panel having at least one edge bent over to provide a relatively narrow elongated flange which is joined to a relatively rigid metal base member by spot welds positioned along the length of said flange at relatively close intervals, said method comprising the steps of: a. cutting said panel along said edge flange relatively closely adjacent said base member to remove the body portion of said panel while leaving said flange joined to said base member; b. separating an end portion of said flange from said base member and bending the free end portion away from said base member; c. providing a tool having a bifurcated end portion adapted to be rotated about an axis generally aligned with the longitudinal extent of the bifurcation; d. positioning the free end portion of the strip in the bifurcation; and, e. rotating the tool about said axis to cause said flange to be wound up said tool and said spot welds sequentially broken to thereby remove said flange.
 2. The method as defined in claim 1 wherein said tool is rotated at intermittently varying revolutions per second.
 3. The method as defined in claim 1 wherein said tool is rotated at below 10 revolutions per second.
 4. The method as defined in claim 1 wherein said tool is rotated intermittently.
 5. The method as defined in claim 1 wherein said flange is wound upon said tool in a direction such as that the portion of the flange which has not been removed is always between the tool and the base member. 